In terms of committees, the power to send for records and papers is delegated from the chamber. If the chamber itself was to set limits, for example, that certain documents are to be consulted only in camera, the committees, as creatures of the House, would have to obey those limits.
Based on the standing powers of standing committees, they have the power to send for records. There's no limit. If a committee asks for documents and they are not provided, the committee has various options. It could decide not to pursue the investigation or the search for these documents. It could decide to compromise and have a discussion with the party that is resisting the provision of documents to see if safeguards or measures that will protect confidentiality will address any concerns that have been expressed. Committees could insist on the production of unredacted documents.
If the committee insists on the production of unredacted documents and the documents are not provided, then the committee cannot itself enforce the failure to provide documents. The committee has to report to the House and then the matter can be raised as a question of privilege in the House of Commons.